Question is :

5. Write down the probability distribution of a Poisson random variable with

parameter

The average number of earthquakes in a certain region is 2 per week. Assume

that, in any time interval, the number of earthquakes occurring has a Poisson

distribution, calculate

(i) the probability of no earthquakes in a given week;

(ii) the probability of at least 1 earthquake in a given week;

(iii) the probability of at least 3 earthquakes in a given fortnight.

(iv) Calculate the probability that the time until the next earthquake, starting from now, is at least 1 week.

I need help on part (iv) my answers for the others parts are :

i) P(x=o) (e^-2 x 2^0)/0! =0.1353

ii)

iii)

these are my answers.

can someone please help me on part (iv)

thanks